Hydraulic relief valve



F 1, 4 J. F.IMELICHAR nmmuuc RELIEF VALVE Filed Dec. so, 1943 Fig.1. 55

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atented? Fe. El, 1947 STATES RAULIC RELIEF VALVE Joseph F..Melichar, Cleveland, Ohio, asslgnor to The Parker Appliance Company, Cleveland, Ohio, a corporation of Ohio I Application December 30, 1943, Serial-No. 516,259

1 claim. ((31.137-53) The invention relates generally to valve structures and primarily seeks to provide a novel, simple and inexpensively constructed hydraulic re-' lief valve wherein the yieldably seated valve means is .so-constructed and arranged; as to offer a minimum of resistance to normal pressure flow,

in which the valve member is held againstits seat by a relatively light spring becaus of the provision on.the valve member of a-relatively small annular surfacepresented for unseating engagement by the pressure fluid, and in which the valve member and its seat are so related as to provide for a substantially large pressure relief fiow upon slight lifting of the valve member from its seat.

With the above and other objects in view that will hereinafter appear, the nature of. the invention will be more fully understood by following the detailed description, the appended claim and the several views illustrated in the accompanying drawing. V

In the drawing:

Figure l is a central vertical cross section' of the improved valve structure.

Figure 2 is an inverted plan. view.

In the example of embodiment of the invention herein disclosed, the valve includes a gen-.

The body 5 is providedvwith a central longi-. tudinal'bore extending through both ends in the beyond the transverse bore in, and at the posi tion opposite the bore ill the valve sleeve is pro-- less than the internal diameter of the valve bore 8 so as toprovide an annular passage surrounding the'extension ill. The extension I8 is provided with a coniform seat surface IS.

A long valve member 20 in the form of a sleeve is mounted with a snug sliding fit in the valve bore 8 and extends from the position of the seat extension surface H to a point well vided with ports 2! which afford communication between the interior of the valve sleeve and the relief port Ill. Near its lower end the valve sleeve is provided with an inward offset 22 presenting an abutment shoulder 23 for engagement with one end of the compression spring 25 which is mounted Within the sleeve valve 20. An annular recess25 is formed in the offset 22;, and a packing ring 26 is mounted in the recess for sealing the valve bore 8 against leakage directly to the relief bore ll) about the exterior of the valve sleeve. Below the offset 22 the end of the valve member 20 presents an annular, relatively small area 21 for contact with pressure fluid about the exterior of the seat head or extens pn H8 in the manner clearly illustrated in Figure 1. The inner edge of the valve sleeve end engages in line contact with the coniform seat surface I 9 as at 28. Theofiset 22 also presents a shoulder 29 which opposes the coniform seat surface IB'in parallel spaced relation as shown manner clearly illustrated'in Figure l. A transverse pressurebore 9 extends through the body 5 and intersects the lower portion of the valve bore 8. A transverse relief bore I0 extends through the body a considerable distance above the pressure bore 9 and also intersects the valve bore 8 as at Hi to a mounting plate l5 which is in turn secured by screws IE to theend of the body extension .7.

The valve seat plug H is provided with a reduced diameter cylindriform extension I l which is disposed opposite the cross bore 9 in the manner clearly illustrated in Figure 1 so as to present a resistance to normal pressure fluid flow through the said bore. On the upper end of the extension I1 is mounted a valve seat enlargement [8 which has an external diameter I and pin 3% so as to protect them against tamperin Figure 1.

The compression spring 24 extends beyond the end of the sleeve valve 20 remote from the coniform seat 19 and engages the abutment nut 30 adjustably mounted in the internally threaded upper end 3| of the bore 8. The adjustable abut ment nut 30 is equipped with a non-circular central opening 32 which slidably receives a non-circular adjuster stem 33. The stem 33 extends above the nut and is equipped with a transverse turning pin 36 which engages in selective cross recesses in the end of the body extension 6 for securing the pin and stem against rotation. A

closure cap 36 threadably mounted on the body extension 6, as at 31, covers the adjuster stem 33 It will be obvious that the spring 24 normally holds the valve member or sleeve 20 seated against the coniform seat surface l9, and the resistance to opening of the valve by pressure exerted upon the small annular area 21 at the seated endof the valve member 20 can be varied by turning the nut 30. When it is desired'to adjust the position of the nut 30 so as to vary the eiiective value of the compression spring 3|, the cap .36 is re\ moved and the pin- 34 is lifted out of the secur-. ing recesses and-used asa turning head to rotate the nut, 1

The valve structure described hereinabove is simple and eflicient in operation and can be manufactured at a relatively low cost. 50 long as pressure inthe pressure line cross bore 9 remains at or'below the predetermined maximum, the

P i 4 sure line connection bore and the valvebore; a

long valve sleeve slidable in said valve bore and having an end thereof disposed for normally ensaging in line contact against said coniform seat a and presenting an annular surface transversely;

of the valve bore in opposition to pressure of fluid surrounding said extension, and a spring norrelief valve 20 will remain seated and pressure flow through the bore 9 will go on substantially uninterrupted because of the particular shaping of the seat plus I l opposite said bore. Whenever the pressure in the bore exceeds the maximum predetermined by addustment of the nut 30, said pressure acting upon the relatively small annular end surface 21 of the valve sleeve 2il-will unseat the valve and provide relief of pressure upwardly through the sleeve 20 and through the side wall ports 2i into the relief bore Ill. Byreason of providing the particular form of valve and seat structure herein disclosed, it is possible to use a relatively light spring to maintain the valve member in its normal, seated position. Also, when the valve member is unseated, only slightly, a relatively large relief flow passage results.

It is to be understood that the details of construction of the cooperating parts can be variously changed without departing from the spirit and scope of the invention, as defined in the appended claim.

Iclaim: A hydraulic relief valve comprising a casing body having an elongated relief valve bore there"- in, a pressure line connection bore disposed transversely of and communicating with said valve bore and a return or drain line connection bore communicating with said valve bore and spaced therealong from said pressure line connection bore, a valve seat plug closing'the valve bore adjacent the pressure line connection bore and having an extension therebeyond which terminates in a coniform seat and is smaller in diameter than said valve bore so as to provide a surrounding annular passage communicating between the presand communicating between its interior and said return bore and also an inward offset spaced a a maliy holding the sleeve on its seat but compressible upon imposition or a predetermined pressure on the seated end of thesleeve to permit unseating of the sleeve and relief of pressure through the sleeve to the return or drain line connection port, said sleeve being of a length for extending beyond the return line bore and for encasing a major part or the length of said sprin said sleeve also having an aperture opposite the return bore short distance from the valve seat engaging end thereof and providing a shoulder abutment for the spring means, said ofiset including a wall portion opposing the coniform seat in parallel spaced relation and spaced by'a cylindrical wall portion of short length extending from the sleeve end portion engaging in line contact with the seat, said offset also having an annular groove therein wherein is mounted a sealing ring engaging in sealing contact with the wall of the elongated relief valve bore.

JOSEPH F. MELICHAR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Canner Dec. 12, 1911 

